Multiple part set screw



Nov. 13, 1951 D. A. WlELAND MULTIPLE PART SET SCREW Filed Jan. 7, 1948 \ATTCI RNEYS Patented Nov. 13, 1951 U M T ED STATE S PATENT OJFFI C E PART SET SCREW 1 Daniel A. Wieland, ,Hagerstown, Md.

Application January '7, 1948', SerialNo. 981

5-4 Claims.

1 This invention relates 'to improvements in multiple part set screws; and :more particularly to :a two pieceset-screw.

An object of the invention is "to provide a two piece set screw, having .a large-outer threaded" body provided with van internal threaded bone that is adapted to receive a small .set screw j body therein, wherebyiboth thehOlltElUbOdY and :theinner screw are provided with looking action in their combined operation.

*With the above and other objects and :advan- "tages in view, the invention :is hereinafter more fully described, claimed-and illustrated in @the accompanying drawing ."in which:

Figure 1 is an elevational view :of an assembly utilizing anaerriboldimentlof the invention;

Figure 2 is a vertical, sectional view on the line 2-2 of Figure 1';

Figure 3 is a vertical, sectional view .01 ea modified form of the invention;

Figure 4 is a bottom plan view .of a modified form of the inner screw of Figure 2, showing the flat end of the set screw' with a knurled or roughened surface;

Figure dis a top plan viewofa modified form of assembly. I

Referring more in detail to the drawings, and more especially to Figures 1 and 2, the set-screw assembly embodying the invention-is seen to comprise an outer set screw body H) which is provided with the external screw threads II. The set screw body ID, by means of the threads H, is threaded into the tapped bore l2 of a part [3, which it is desired to retain in fixed relation to a part I l. The set screw body I0 is provided with a centrally located hex-shaped bore IS in which is placed a similarly shaped wrench whereby the set screw body [0 is threaded into the bore I2.

Centrally of the bore IS, the set screw body It is provided with a tapped bore l6 that is adapted to receive the externally threaded inner set screw II. The set screw l I is provided centrally thereof with a hex-shaped bore I8 which is adapted to receive a similarly shaped wrench which is of smaller dimensions than the wrench used to tighten the set screw body I 0.

The lower end of the set screw body l0 about the bore I6 is provided with the conventional cup point, the lower edge l9 of which cup is adapted screw body 'I 0 is turned until it bottoms against the part M. It is then turned slightly back to clear the part Hi. The set screw [7 isthen'installed in the bore 1'6 and drawn into tight engageinent'with the part I4. The set screw body H is then tightened 'toiurther force the set screw I7 into the part I4 and lock the assembly in 'engagement with the part '14.

To remove the set screw, the body I0 is first loosened to break its locking effect, and the "set screw [7 is then backed out. It'will be noted that the threads of the here It and the threads of theset screw 17' are of a finer pitch than the threads H of the set" screw body 10. Thus a locking eifect is achieved.

In :the modified-form shown in Figure 3, the .set screw body 113 is identical in all respects 'to the set screw body H '01 Figure 2. Set screw body It has theexternal threads l l receivable in the tappedbore 12' of the part l3" placed on the part [4, as previously described. The set screw :body 19 has the central hex-shaped bore l5 Centrallyof the bore 'I5the setscrew body l0 is provided with a tapped bore 115 which is adapted to receive the externally threaded pin type set screw 21. The set screw 21 is provided centrally "thereof With a hex-shaped bore 22, WhiC'h'Jls also adapted to receive a wrench.

In this assembly, the part It is provided with a drilled opening 23 which is adapted to receive the pin end 24 of the set screw 2|. The pin end 24 is shaped so as to make convenient entrance into the opening 23. The lower end of the set screw body l0 about the bore [6 is provided with the conventional cup point, the lower edge l9 of which is adapted to engage the part I4.

In Figure 3, it will be noted that the set screw 21, about the pin 24, at its upper end, is provided with a tapered shoulder 25. Thus the set screw 2| will draw tight into the opening 23, permitting a generous tolerance as regards the accuracy of the opening 23. It will also be seen that when the final turn of the set screw body I0 is made, the tapered shoulder will be forced further into the opening 23, producing a very tight fit on the shear line of the parts 13' and M.

The use of the modified form of the invention is similar in all respects to the use of the first form described.

The use of the latter set screw combination for a pin application provides great advantages over the conventional straight or tapered pin application. No special machining accuracy is required, such as reaming for the pin, just a straight openin of reasonable accuracy is needed to permit efficient operation of the combination.

The size of the assembly is determined by the strength required by the connection or the torque strength needed.

No mutilation of parts occurs in the installation or removal of the set screw assembly, and a tight fit is provided at all times. The threads of the two parts are of different pitch and different helix angles, thus the parts, when used in combination, as explained, provide a locking action similar to the effect of a lock nut.

In the modified form of set screw 26 shown in Figure 4, the conventional cup point with its edge 20 on the bottom of the set screw H, as shown in Figure 1, has been changed to show a fiat knurled or roughened surface 21 which is used to form a gripping contact with the part H.

In the modified form shown in Figure 5, the assembly is as previously described for all its various elements, except that the set screw body is provided, on its upper edge, with the opposed alined slots 28, which are adapted to receive a spanner wrench which would be used in the event the set screw is of a length as to make it impossible to use the standard inside hexagonshaped wrench.

There has thus been provided a set screw assembly which, it is believed, will efficiently perform the tasks for which it has been designed.

It is believed that from the foregoing description, the structure and operation of the invention will be apparent to those skilled in the art, and it is to be understood that changes in the minor details of construction, arrangement and combination of parts may be resorted to, providing they fall within the spirit of the invention and the scope of the appended claims.

Having thus described the invention, what is claimed as new or desired to be secured by Letters Patent is:

1. A set screw assembly comprising an outer body portion provided with external threads, a hex-shaped bore centrally of said body portion, an internally threaded bore at the bottom of said hex-shaped bore, a set screw threaded into the internally threaded bore, the set screw having a hex-shaped bore which is in axial alinement with the hex-shaped bore of the outer body portion and the threads of the bore of the outer body and the threads of the set screw being of finer pitch than the external threads of the set screw body, a pin end on the lower end of the set screw having a tapered surface forming a gripping surface thereon and the lower end of the set screw body is provided with a gripping surface.

2. A set screw assembly comprising an outer body portion provided with external threads, a hex-shaped bore centrally of said body portion, an internally threaded bore at the bottom of said hex-shaped bore concentric with said hex-shaped bore, a set screw threaded into the internally threaded bore, the length of the threaded portion of the set screw and the length of the internally threaded bore being of a length less than the lengthof the outer body portion, the set screw having a hex-shaped bore which is in axial alinement with the hex-shaped bore of the outer body portion and the threads of the bore of the outer body portion and the threads of the set screw being of finer pitch than the external threads of the outer body portion, the lower end portion of the set screw and the lower end portion of the outer body portion each having a tapered surface thereon to provide a gripping surface.

3. A set screw assembly as in claim 2 wherein the set screw and the outer body portion each have a second tapered surface reversely tapered to said first tapered surface to provide a biting edge on said set screw and outer body portion.

4. A set screw assembly as in claim 2 wherein said set screw is provided with a locking pin merging with and extending below the tapered surface thereof.

DANIEL A. WIELAND.

REFERENCES CITED The following references are of record in the file of thispatent:

UNITED STATES PATENTS Number Name Date 679,927 Warman Aug. 6, 1901 866,184 Brison Sept. 17, 1907 869,086 Hoffman Oct. 22, 1907 2,197,875 Odin Apr. 23, 1940 2,201,087 Hallowell May 14, 1940 2,314,274 Hallowell Mar. 16, 1943 

